Following opinion polls and consultations with the Irish Houses of Parliament in December 2008, the Irish government asked other European leaders for certain assurances and guarantees on matters which were clearly important to Irish voters. In response, the European Council (heads of government) adopted a decision in June 2009 to provide guarantees that certain Irish laws will not be affected by the Lisbon Treaty in the areas of:

The right to life, family and education Taxation Security and defence The leaders formally agreed to add this decision to a future EU Treaty as a protocol. The leaders also formally agreed to activate the Lisbon Treaty provision to retain one Commissioner per Member State, once the Treaty was ratified.

In return, the Irish government agreed to put the Treaty to the Irish people once more, under these new conditions. The Irish people go to the polls to make their decision on Friday 2 October 2009.

Although the poll proper starts in Ireland at 7 a.m. on Friday, 2 October, voting in the Lisbon Treaty Referendum began on 30 September 2009 for the almost 800 voters living on islands off the Donegal coast in the north-west of Ireland. They will be followed on 1 October by 2,000 people living on islands off the Galway, Mayo and Cork coasts. People living in the islands vote ahead of the rest of the country because of the risk of being cut off by bad weather.

Voting stops at 10 p.m. on Friday but the counting is manual and does not begin until Saturday morning, 3 October.  First results will be known during that morning and the count can be followed online at the State broadcaster www.RTE.ie as well as at www.referendum.ie. The final result should be known on Saturday evening.

Over 500 television crews, radio and print journalists and bloggers from all over the world have received accreditation to attend the count in Dublin Castle. This includes over 160 Irish journalists. Most of the rest are from other EU countries with Germany and the UK being among the best represented.